Condenser structure for absorption refrigeration apparatus



1952 s. M. BACKSTROM 2,619,809 CONDENSER STRUCTURE FOR ABSORPTIONREFRIGERATION APPARATUS Filed April 6, 1946 2 SHEETSSHEET 1 1 Y IN V ENTOR. WW 3W WM S. M. BACKSTROM Dec. 2, 1952 CONDENSER STRUCTURE FORABSORPTION REFRIGERATION APPARATUS 2 Sl-lEETS-SHEET 2 Filed April' 6,1946 XXX XX'XXXXX A9" I E J INVENTOR. wy/4am Patented Dec. 2, 1952CONDENSER STRUCTURE FOR ABSORPTION REFRIGERATION APPARATUS SigurdMattias Backstriim, Stockholm, Sweden, assignor, by mesne assignments,to Aktiebolaget Elektrolux, Stockholm, Sweden, a corporation of SwedenApplication April 6, 1946, Serial'No. 660,054 In Sweden April 17, 194513 Claims. (Cl. 62-1195) This invention relates to air-cooled absorptionrefrigerating apparatus of the inert gas typ especially apparatus whichis adapted for domestic or household use, and has for its object toprovide an improvement to simplify the condenser system of suchapparatus to obtain greater latitude in mounting and positioning theapparatus in a refrigerator cabinet.

Whereas in compressor-operated refrigerating apparatus a great latitudein the choice of the condenser construction is afforded, certain factorsrequire consideration in the construction of the condenser for anabsorption refrigerating apparatus of the inert gas type. In suchapparatus relatively small driving forces are developed to efiect liquidcirculation and cause inert gas circulation. Even a very small increasein pressure in any part of the apparatusmay Wholly change the differentliquid levels therein to such an extent that suitable liquid circulationcannot be effected. Such differences in pressure would easily arise ifthe resistance to flow of the boiler vapours were increased.Additionally, the presence of the inert gas also presents specialproblems in the construction of the condenser.

With regard to these factors, one single pipe coil heretofore hasgenerally been used for the condenser of the apparatus and in certaininstances a plurality of Such pipe coils connected in series. In sucharrangements a venting conduit has been provided for the inert gas whichextends from the upper part of the condenser, or the conduit fordelivering refrigerant condensate has been employed so that both liquidand gas unobstructedly pass therethrough. Further, it has been proposedto provide condensers of the kind heretofore employed in which the outersurface of the pipe coil alone provides adequate heat dissipatingsurface to reject and give up heat of condensation to air flowingin-contact therewith. However, in practice it has not been possible, atleast in apparatus adapted for household or domestic use, to employ apipe coil having adequate heat dissipating surface for air cooling andpresent relatively small resistance to flow of boiler vapours therein.Accordingly, it has heretofore been necessary to arrange cooling fins onthe condenser pipes. The long interconnected condenser pipes in the formof coils, in order to operate in a satisfactory way, requirespositioning the apparatus in suchmanner that blocking of the condenserby liquid condensate therein is avoided. The longer the condenser pipeand the less the cross-sectional area of the passage of the p pe mp oyert o e h r b em must-be taken into consideration. In accordance with theinvention the foregoing problems areovercome by providing a condenserfor absorption refrigerating apparatus of the inert gas type which isconstructed in such manner that a plurality of paths of flow are formedfor boiler or refrigerant vapours which are connected in pare allel andto which a vent conduit is connected to a region at an upper part ofsuch paths of flow) and supplying the boiler or refrigerant vapours tothe condenser so that a column of such vapours is effectively utilizedto produce a driving force and promotecirculation of the, vapours in theparallel paths of flow.

The invention, together with the above and other objects and advantagesthereof, will be more fully understood upon reference to the fol-'-lowing description and accompanying drawings forming a part of thisspecification, and of which:

Fig. 1 is a view more or less diagrammatically illustrating a condenserembodying the invention for use in an absorption refrigerating apparatusof the inert gas type;

Fig. 2 diagrammatically illustrates such absorption refrigeratingapparatus of the inert gas type? Figs. 3 to 6 illustrate furtherembodiments'of condensers in accord with the invention which are formedof pipe coils;

Fig. 7 is a perspective view illustrating a still further embodiment ofa condenser in accord with the invention which is formed of plate-likemembers; and

Figs. 8 and 9 are side and top plan views, respectively, of thecondenser shown inFig; '7. p

Fig. 1 shows a condenser having conduits for connection in absorptionrefrigeration apparatus employing inert gas and of a type like thatillustrated in Fig. 2. The condenser-comprises two end headers orcollector pipes l0- and ,l I. both ends of'the former being closed; Bothcollector pipes are interconnected with a number of essentially parallelcondenser pipes I2, which preferably have a cross-sectional area lessthan that of the collector pipes. As shown, the pipe system described isstep-like in form and is intended to be mounted in the rear compartmentof a household refrigerator cabinet and adapted to be cooled by air, thenatural draft circulation of which is partly due to heat rejected fromthe absorber of the refrigerating apparatus also disposedin the flueformed at the rear apparatus compartment. In the following descriptionsuch a system will be designated a pipe group in a structural'element incondenser systems of large size; Refrigerant vapours expelled from theboiler or vapour expulsion unit of the apparatus, like the boiler 20 inFig. 1, for example, are supplied to the collector pipe It through aconduit 2 I, which is connected between the two uppermost condenserpipes I2. The condensate formed in the pipe system flows from thecollector pipe II, towards which the condenser pipes I2 suitably mayincline, through a conduit M which is shaped to form a liquid trap andis connected to the evaporator of the refrigerating apparatus, like theevaporator 21 in Fig. 1, for example. By providing the U-trap in conduitIt the: condenser is separated from the gas circulating system. of theapparatus. However, in order to permit inert gas to vent from thecondenser system the upper part of the collector pipe I I isconnectedtoa vent pipe I5, which communicates with the gas circulatingsystem of the refrigerating apparatus, as at the gas heat exchanger.Such a vent connection from a condenser to the gas circuit is indicated.at I in Fig. 2, for example;

When the apparatus is initially started, the condenser mainly containsinert gas, such as hydrogen gas, which prevents condensation of thepenetrating refrigerant vapours. The densityof such vapours, such asammonia vapour for example, is greater than that of the hydrogen gas;and consequently the greater part of the condenser is filled upwardlyfrom the bottom thereof with ammonia vapour, whilethe hydrogen gas willbe gradually forced out from one condenser pipe after another, beingfinally forced upwardly through the pipe II and the vent pipe l5.However, all of the condenser pipes need not necessarily be filled withammonia vapour at such a high pressure that condensation will takeplace- Ifthe cooling of the condenser is good, itis possible that such alarge'part of the vapour quantity may condense in the lowest three pipesso'that. the.- partial pressure of the refrigerant vapour in the: uppercondenser pipes'will not be sufiiciently high for condensation to takeplace therein. In such case the. upper condenser pipes stillremainfilled with hydrogen gas and act to a certain extent as a pressureequalizing vessel. In the arm A of the end header or collector III,which isfilled with the heavier ammonia vapour, a driving force isproduced which causes circulation of. such vapour when some of thecondenser. pipesare filled with hydrogen gas'and the vapour in anuncondensed stateor vapour phase tends to seek a path of flow leading tothe ventpipe I5; This circulation of vapour grad- 113,113 brings intooperation the requisite number of. condenser. pipes for properfunctioning of the condenser.

InFig; 2.. is illustrated absorption refrigerating apparatus oftheinertgas type; Such apparatus,;wh-ich..is well known, includes theboiler 28 in which. refrigerant. vapours are expelled and through a.vapour conduit 2| supplied'to thecondenser system 22. The liquidcirculating pump of the. apparatus is denoted by 23, its air-cooledabsorber by 24 and its absorber vessel by 25. The absorber andthe'absorber vesseloom'municateina well known manner through a liquidheat exchanger 26 with the boiler 20 and the liquid circulating pump 23,respectively; The evaporator of-the apparatus is denoted'by 21 and itsgas heat exchangerby' 23. These parts of apparatus form, together-withthe absorber and the absorber vessel, the gas circulating system of:the-apparatus, which is built up in a well known manner.

In Fig. 2 the condenser system 22 includes two pipe coils 30 and 3|,disposed in two parallel vertical planes. The upper part of the coil 30is connected to the vapour conduit 2|, while the upper part-of thecoil 3isconnected to the pressureequalizing vessel of the apparatus, denotedby 32, for which vessel the coil 3| at the same time serves as a drainconduit for condensate which may be formed therein. The pressureequalizing vessel is connected by the vent conduit I5 to the gascirculating system of the apparatus. The lower ends of both the pipecoils. 3-0. and.3| are. connected to a common conduit 3d,. through whichrefrigerant condensate is fed to the evaporator 21. The conduit 34 isarranged in. heat exchange relation with the conduitilfi, through whichthe inert gas flowing to the absorber is conducted from the evaporator2.3. It is to be understood that the condenser system of Fig. 1 anddescribed above may be connected in absorption refrigeration apparatusof the kindshown inFig.

Figs. 3 and 4 show further embodimentsof the condenser system accordingto the. invention. The arrangementaccording to Fig. 3 comprises two pipegroups coupledtogether and of thetype shown. in Fig. 1, both pipe groupssuitablybeing of the same dimensions and connected by a con-.- duit All.The reference characters correspond to those. of Figs. 1 and 2. Theboiler vapours hence flow from the conduit 2| into the first pipe group,which is denoted by 4|, whereby thegas forced through. the. conduit 40is transferred to. the lowest part of the pipe group 42. and through itsleft-handend header or collector pipe to thepressure equalizing vessel32. Both right-hand arms or end headers of the pipe groups areconnected. to a conduit 43. through which refrigerant condensate isconducted through the liquid trap- I4 to the evaporator of theapparatus-Fig. 4 shows acondenser system comprising three pipe groups accordingto: Fig. 1. The vapour conduit. ZI-is connected to theleft end headerorarm of each of the three pipe groups 4|, 42 andM at pointswhich' are:located between the tw uppermost-horizontal pipes of each pipe group.The upper ends of the left-hand end headers or vertical pipes ofthe pipegroups are mutually interconnected by the conduit 45; The inert gasisforced out from one system after the other and is vented through theupper-pipe of the pipe group-1M". to the vent'conduit I5. Thedifference/in density in the left and right standpipes or-risers of thepipe groups, described in connection. with Fig. 1, will then bring aboutthe successive forcing'out of the inert gas from one group afteranother."

Figs. 5'and 6 showfurther'embodiments of the condenser system accordingto the invention and differ from the earlier embodiments essentially inthatthe pipe groups are placed in different horizontal planes parallelto another. The ref erence characters correspond to those of thepreceding figures. The connection of the pipe groups is believed to besufiiciently clear in the drawings. As shown in Fig. 5, the differentpipe groups are connected to a common outlet conduit {36' forcondensate, which is conducted through it is suitable to arrange thehorizontal pipe .distances in such manner that they are disposed groups,respectively, in the manner described above, it is possible, without anydanger of liquid blocking, to select pipes of small internal diameter insuch number and with such a large external jacket or heat dissipatingsurface that the condenser will function properly with air-cooling andyet not require additional heat dissipating fins or similar members. Inthose cases when for some reason or other it is desired to limit thetotal pipe length of the condenser, heat dissipating fins or the likemay, of course, be employed in a Well known manner. It is desirable insuch case to arrange the fins so that the upwardly flowing air streampassing from the lower located absorber of the refrigerating apparatuswill pass in intimate contact with the fins in the fin packet and willbe directed through the central part thereof. This is accomplished byarranging the condenser pipes in the packet so that pipes will bedisposed over a greater part of the horizontal cross-section of the airflue.

The invention may be further developed in such manner that thepipegroups are replaced by fiat hollow structures welded from sheetmetal members, as diagrammatically shown in Figs. '7,

-8 and 9. Fig. 7 shows a condenser system comprising three similar flathollow structures 55,

the upper parts of which are connected by conduits 5| and 52. The supplyconduit for refrigerant vapours is denoted by 2| and the dischargeconduit for refrigerant condensate by hi. In order to couple the hollowstructures 58 together it may be suitable to form the structures in themanner shown in Fig. 8. Fig. 9 shows a condenser system built up ofmembers like that shown in Fig. 8. As shown, the hollow structures 50are formed of pressed plates which preferably are congruent with respectto one another and welded together in pairs along their edges and whichin other respects are shaped and joined together in a well known mannerin the manufacture of heat-radiators. Due to the high pressure generallyprevailing in the apparatus, which pressure may exceed 20 atmospheres,the opposing plates of each hollow structure 53 are united together notonly along their edges but also at a. number of welded points 55. Atthese points the plates before being welded together are impressed insuch a way that, when the plates are placed together with the concavesides against each other, the convex surfaces of the impressions willlie in pairs against each other. Thereafter the plates of each hollowstructure are united together by electrical resistance welding. In orderto facilitate the mounting of the hollow structures 50 the connectingopenings are arranged in ears 56, which then, as will be clear from Fig.9, will be placed close to each other,

thus forming through conduits 5! to which the interconnecting conduitsof the apparatus are coupled. Byconnecting the vapour conduit 2lfromtheboiler to the upper ends of the flat hol- .6 low structures 50,as shown in Fig. 'l, a'fiow' within the system will be effected, whichcauses an equalization of the loading of the condenserdue to thehydrogen gas being gradually forced out through the vent conduit.

In view of the foregoingit willnow be understood that in the differentembodiments illustrated and described above refrigerant: vapour isintroduced into an end header or a collector of a condenser unit to forma column. of such vapour which is effectively utilized as a drivingforce to promote circulation of refrigerant vapour in a plurality ofhorizontally extending passages connected at their ends to thevertically extending end headers. Each end-header independently. of theother end header serves to establish fluid communicationbetween allofthe horizontally extending passages embodied in each condenser unit orsection and connected thereto.

In Figs. 1, 3, 4 and 5 the conduit 2| for conducting refrigerant vapourfrom the boiler or vapour expulsion unit is connected at a region of theend collector which is located between the highest and next highesthorizontally extending pipes or pipe elements'forming the passageways.In the different embodiments the horizontally extending passages orpipes are distributed in a vertical range between a low and higher-leveland disposed at three or more different levels. Hence, refrigerantvapour is introduced into a vertically extending passage or end headerat a region which is above the connection thereto of at least two ormore pipes at different levels and above at least half of the differentlevels at which the horizontally extending passages or pipe elements aredisposed.

The invention is not to be limited to the embodiments shown but may bevaried in several ways with in the scope of the basic inventive idea. Itis essential for the condenser system to be vented from a region thereoflocated sufiiciently. high within the system so that no hydrogen gasworth mentioning will collect above such region. Further, the condensersystem desirably should be mounted in such manner that, due to, thedifference in density of inert gas and refrigerant vapour, an internalcirculation will be established and an increasingly greater part of thecondenser will be made available to function and liquefy refrigerantvapour by displacing hydrogen gas through the vent conduit.

Reference is made to applicants divisional ap plication Serial No.210,908, filed February 14, 1951, which claims features of theabsorption refrigeration apparatus disclosed in Figs. 7, 8 and 9.

I claim:

1. In air-cooled absorption refrigeration apparatus containing an inertgas and refrigerant fluid which in vapor phase is denser than the gas, agas circuit including evaporator structure, and a vapor expulsion unitfor producing refrigerant vapor, means for supplying liquid refrigerantto the evaporator structure comprising condenser structure includingfirst and second vertically disposed conduits in spaced apart relation,a plurality of horizontally extending pipes arranged at least at threedifferent levels, each of said pipes having one end thereof connected tosaid first conduit .and the opposite end thereof connected to saidsecond conduit, the cross-sectional areas of said conduits being greaterthan the crosssectional areas of said pipes and forming vertical endheaders, said first conduitconstituting means for establishing fluidcommunication between all ofsaid pipes which are embodied in saidcondenser structure and connected thereto, said, second conduitconstituting means for establishing fluid communication between all ofsaid pipes which are embodied in said condenser structure and connectedthereto, conduit means for conducting refrigerant vapor from the vaporexpulsion unit to an end header of said condenser structure at a'levelwhich is above the connection thereto of the lowest pipe and below theconnection thereto of the highest pipe, conduit means communicating withan end header of said condenser structure for conducting liquidrefrigerant therefrom to the evaporator structure, and conduit meanscommunicating with an upper part of said condenser structure for ventinginert gas therefrom to the gas circuit;

2. In air-cooled absorption refrigeration apparatus employing hydrogenas an inert gas and ammonia as a refrigerant, a gas circuit includingevaporator structure, and a vapor expulsion unit for producingrefrigerant vapor, means for supplying liquid refrigerant to theevaporator structure comprising condenser structure including first andsecond vertically disposed conduits in spaced apart relation, aplurality of horizontally extending pipes arranged at least at threedifferent levels, each of said pipes having one end connected to saidfirst conduit and the opposite end connected to said second conduit, thecrosssectional areas of said conduits being greater than thecross-sectional areas of said pipes and forming vertical end headers,said first conduit constituting means for establishing fluidcommunication between all of said pipes which are embodied in saidcondenser structure and connected thereto, said second conduitconstituting means for establishing fluid communication between all ofsaid pipes which are embodied in said condenser structure and connectedthereto, conduit means for delivering refrigerant vapor from the vaporexpulsion unit to said first conduit at a region between the connectionsthereto of said pipe at the highest level and the pipe at the nexthighest level, conduit means communicating with the lower end of saidsecond conduit for conducting liquid refrigerant therefrom to theevaporator structure, all of said pipes being inclined to drain liquidtherefrom by gravity to said second conduit, and conduit meanscommunicating with an upper part of said condenser structure for ventinginert gas therefrom to the gas circuit.

3. In an air-cooled absorption refrigeration apparatus containing aninert gas and refrigerant fluid which in vapor phase is denser than thegas, a gas circuit including evaporator structure, and a vapor expulsionunit for producing refrigerant vapor, means for supplying liquidrefrigerant to the evaporator structure comprising condenser structureincluding first and second vertically disposed conduits in spaced apartrelation, a group of horizontally extending pipes distributed verticallyin the space between said conduits, each pipe having one end connectedto said first conduit and the opposite end connected to said secondconduit, said conduits being of greater diameter than said pipes andforming vertical end headers, each of said conduits constitutingindependent means for establishing fluid communication between all ofsaid pipes which are embodied in said condenser structure and connectedthereto, conduit means for conducting refrigerant vapor from the vaporexpulsion unit to an end header of said condenser structure at a regionwhich is above the connection thereto of at least two or more pipesatdifferent: levels, conduit means communicating with an end header ofsaid condenser structure for conducting liquid refrigerant therefrom tothe evaporator, and conduit means communicating; with an upper part ofsaid condenser structure for venting inert gas therefrom to thegascircuit;

4. In an air-cooled absorption refrigeration apparatus containing aninert gas and refrigerant fluid which in vapor phase is denser than thegas, a gas circuit including evaporator structure, and a vapor expulsionunit for producing refrigerant vapor, means for supplying liquidrefrigerant. to the evaporator structure, comprising condenser structureincluding first and second vertically disposed conduits in spaced apartrelation, 2. group of horizontally extending pipe elements between saidconduits which are disposed at three or more difierent levels, all ofsaid pipe elements at one end of the group being connected to said firstconduit and at the opposite end thereof being connected to said second,conduit, each of said first and second conduits forming a vertical endheader which constitutes means for establishing fluid communicationbetween all of said pipe elements which are embodied in said condenserstructure and connected thereto, conduit means for deliveringrefrigerant vapor from the vapor expulsion unit to an, end header ofsaid condenser structure at a region which is above at least half of thedifferent levels at which said pipe elements are disposed, conduit meanscommunicating with an end header of said condenser structure forconducting liquid refrigerant therefrom to the evaporator structure, andconduit means communicatin with an upper part of said condenserstructure for venting inert gas therefrom to the gas circuit.

5. In air-cooled absorption refrigeration apparatus containing an inertgas and a refrigerant which in vapor phase is denser than the gas, a gascircuit including evaporator structure, and a vapor expulsion unit forproducing refrigerant vapor, means for supplying liquid refrigerant tothe evaporator structure comprising a condenser unit including structureproviding vertically extending passages forming end headers which are inspaced apart relation and also providing a group of horizontallyextending passageways which are distributed in a vertical range andpositioned at three or more different levels, one of said end headersbeing connected to one end of said horizontally extending passages andthe other end header being connected to the opposite end of suchpassages, each of said end headers constituting independent means forestablishing fluid communication between all of the horizontallyextending passageways embodied in said condenser unit and connectedthereto, conduit means for conducting refrigerant vapor from the vaporexpulsion unit to said one end header at a region which is above atleast half of the different levels at which said horizontally extendingpassageways are disposed, conduit means communicating with said otherend header for conducting liquid refrigerant therefrom to the evaporatorstructure, and conduit means communicating with the upper part of saidcondenser unit for venting inert gas therefrom to the gas circuit.

6. In air-cooled absorption refrigeration apparatus containing an inertgas and a refrigerant which in vapor phase is denser than the gas, a gascircuit including evaporator structure, and a vapor expulsion unitforproducing-refrigerant vapor, means for supplying liquid refrigerant tothe evaporator structure comprising condenser structure including agroup of horizontally extending pipe elements distributed in a verticalrange disposed between a low level and a higher level and having pipespositioned at three or more difierent levels, first conduit means forconnecting all of said pipe elements at one end of said group andestablishing fluid communication at such one endof all of said pipeelements which are embodied in said condenser structure, second-conduitmeans for connecting all of said pipeelements at the opposite end ofsaid group and establishing fluid communication at such opposite end ofall of said pipe elements which are embodied in said condenserstructure, third conduit-means for delivering refrigerant vapor from thevapor expulsion unit to said first conduit means at a region thereofwhich is above and below the pipe elements disposed at said low andhigher levels, respectively, fourth conduit means communicating withsaid second conduit means for conducting liquid refrigerant frigerant tothe evaporator structure comprising condenser structure including agroup of horizontally extending pipe elements distributed at three ormore different levels in a Vertical range disposed between a low leveland a higher level, first conduit means for connecting all of said pipeelements at one end of the group and establishing fluid communication atsuch one end of all of said pipe elements which are embodied in saidcondenser structure, second conduit meansfor connecting all of said pipeelements at the oppqsite end of the group and establishing fluidcommunication at such opposite end of all of said pipe elements whichare embodied in saidcondenser structure, third conduit means fordelivering refrigerant vapor from the vapor expulsion unit to said firstconduit means at a region which is above at least half of the differentlevels at which said pipe elements are distributed, fourth conduit meanscommunicating with said second conduit means for conducting liquidrefrigerant therefrom to the evaporator structure, and conduit meanscommunicating with an upper part of said condenser structurefor ventingine t gas therefom .to the gas cicuit.

8. In an air-cooled absorption refrigeration apparatus containing aninert gas and refrigerant fluid which in vapor phase is denser than thegas, a gas circuit including evaporator structure, and a vapor expulsionunit for producing refrigerant vapor, means for supplying liquidrefrigerant to the evaporator structure comprising a plurality ofcondenser sections, each of said sections including first and secondvertically disposed conduits in spaced apart -re-' lation and aplurality of horizontally extending pipesarranged at least at threedifferent levels, 'each of said pipes having one end connected' tosaid'first conduit and the opposite end connected to said secondconduit, the crosssectional areas of said conduits being greater 10 thanthe cross-sectional areas of said pipes and forming end headers, saidfirst conduit constituting means for establishing fluid communicationbetween all of said pipes which are embodied in the condenser sectionand connected thereto, said second conduit constituting means forestablishing fluid communication between all of said pipes which areembodied in the condenser section and connected thereto, conduit meansfor conducting refrigerant vapor from the vapor expulsion unit to theend headers of a plurality of said condenser sections at regions whichare above the connection of the lowest pipe to each such end header andbelow the connection of the highest pipe to each such end header,conduit means communicating with an end header of each such condensersection for conducting liquid refrigerant therefrom to the evaporatorstructure, and conduit means com-,

municating with an upper part of each such condenser section for ventinginert gas therefrom to the gas circuit.

9. In an air-cooled absorption refrigeration apparatus containing aninert gas and refrigerant fluid which in vapor phase is denser than thegas, a gas circuit including evaporator structure, and a vapor expulsionunit for producing refrigerant vapor, means for supplying liquidrefrigerant to the evaporator structure comprising first and secondcondenser sections, each of said sections including first and secondvertically disposed conduits in spaced apart relation and a plurality ofhorizontally extending pipes arranged at least at three differentlevels, each of said pipes having one end connected to said firstconduit and the opposite end connected to said second conduit, thecross-sectional areas of said conduits being greater than thecross-sectional areas of said pipes and forming end headers, said firstconduit constituting means for establishing fluid communication betweenall of said pipes which are embodied in the condenser section andconnected thereto, said second conduit constituting means forestablishing fluid communication between all of said pipes which areembodied in the condenser section and connected thereto, conduit meansfor conducting refrigerant'vapor from the vapor expulsion unit to an endheader of the first condenser section at -a region which is above theconnection of the lowest pipe thereto and below the connection of thehighest pipe thereto, conduit means connecting an upper part of saidfirst condenser section and an end header of said second condensersection, conduit means communicating with an end header of eachcondenser section for conducting liquid refrigerant therefrom to theevaporator structure, and conduit means communicating with an upperpar-t of said second condenser section for venting inert gas therefromto the gas circuit.

10. In aircooled absorption refrigeration apparatus employing hydrogenas an inert gas and ammonia as a refrigerant, a gas circuit includingevaporator structure, and a vapor expulsion unit for producingrefrigerant vapor, means for supplying liquid refrigerant to theevaporator structure comprising a plurality of condenser sections, eachof said sections including. first and second verticallydisposediconduits in spaced apart relation, a plurality of horizontallyextending pipes arranged at least at three. different levels, each ofsaid pipes havingone end connectedto said tional areas of said pipes andforming vertical end headers, said first conduit constituting means forestablishing fluid communication between all of said pipes which areembodied in the condenser section and connected thereto, said secondconduit constituting means for establishing fluid communication betweenall of said pipes which are embodied in the condenser section andconnected thereto,conduit means for conducting refrigerant vapor fromthe vapor expulsion unit to the first conduits of a plurality of saidcondenser sections at regions between the connections to each such firstconduit of said pipe at thehighest level and the pipe at the nexthighest level, conduit means communicating with the lower ends of thesecond conduits of each such condenser section for conducting liquidrefrigerant therefrom to the evaporator structure, all of said pipesbeing inclined downwardly to drain liquid therefrom by gravity to thesecond conduits of said sections, and conduit means communicating withan upper part of each such condenser section for venting inert gastherefrom to th as circuit.

11. In air-cooled absorption refrigeration apparatus employing hydrogenas an inert gas and ammonia as a refrigerant, a gas circuit includingevaporator structure, and a vapor expulsion unit for producingrefrigerant vapor, means for supplying liquid refrigerant to theevaporator structure comprising first and second condenser sections,each of said sections including first and second vertically disposedconduits in spaced apart relation, a, plurality of horizontallyextending pipes arranged at least at three different levels, each ofsaid pipes having one end.

connected to said first conduit and the opposite end connected to saidsecond conduit, the crosssectional areas of said conduits being greaterthan the cross-sectional areas of said pipes and forming vertical endheaders, said first conduit constituting means for establishing fiuidcommunication between all of said pipes which are embodied in thecondenser section and connected thereto, said second conduitconstituting means for establishing fluid communication between all ofsaid pipes which are embodied in the condenser section and connectedthereto, conduit means for conducting refrigerant vapor from the vaporexpulsion unit to the first conduit of said first condenser section at aregion between the connections thereto of the pipe at the highest leveland the pipe at the next highest level, conduit means connecting theupper end of the second conduit of said first condenser section and thelower end of the first conduit of said second condenser section, conduitmeans communicating with the lower ends of the second conduits ofsaid'first and second condenser sections for conducting liquidrefrigerant therefrom to the evaporator structure, all of said pipesbeinginclined downwardly to drain liquid therefrom by V a plurality ofcondenser sections, each-section including first and second verticallydisposed con duits in spaced apart relation, a group of horizontallyextending pipes distributed vertically in the space between saidconduits, each pipe having one end connected to said first conduit andthe opposite end connected to said second conduit, said conduits beingof greater diameter than said pipes and forming vertical end headers,each of said conduits constituting inde pendent means for establishingfiuid communication between all of said pipes which are embodied in thecondenser section and connected thereto, conduit means for conductingrefrigerant vapor from the vapor expulsion unit-to the end headers of aplurality of said condenser sections at regions of each such end headerwhich are above the connection thereto of at least two or more pipes atdifferent levels, conduit means communicating with end headers of eachsuch condenser section for conducting liquid refrigerant therefrom tothe evaporator structure, and conduit means communicating with an upperpart of each such condenser section for vent ing inert gas therefrom tothe gas circuit.

13. In an air-cooled absorption refrigeration apparatus containing aninert gas and refrigerant fiuid which in vapor phase is denser than thegas, a gas circuit including evaporator structure, and a vapor expulsionunit for producing.

refrigerant vapor, means for supplying liquid refrigerant to theevaporator structure comprising first and second condenser sections,each. of said sections including first and second vertically disposedconduits in spaced apart relation, 9.

nected thereto, conduit means for conducting. re-- frigerant vapor fromthe vapor expulsion unit. to an end header of said first condensersection at a region which is above the connection thereto of at leasttwo'or more pipes atdiiferent levels, conduit meansconnecting the upperpart of said first condenser section and an end header of said secondcondenser section, conduit means communicating with end headers of saidfirst and second condenser sections for conducting liquid refrigeranttherefrom to the evaporator structure, and conduit-means communicatingwith an upper part of said second condenser section for venting inertgas therefrom to the gas circuit.

SIGURD MATTIAS BACKSTRGM.

REFERENCES CITED The following references areof record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,958,899 MacAdams May 15, 19342,243,903 I-Iintze June 3, 1941 2,302,091 Anderson Nov. 17, 19422,350,347 Gaugler June 6, 1944 2,422,401 Gaugler June 17, 1947

